If you accidentally paid the wrong expense on the portal, or paid an expense by mistake, and wish to remove the bank payment, go to the My Money tab and choose Expenses. Next to the expense that you paid by mistake, on the right hand side click the options button and choose 'View Expense Summary'.
Choose the View Expense Summary option which will show you the original expense entry with the payment details at the bottom. Next to the payment, on the right hand side click the options button.
Choose the Delete Payment option and a pop up screen will appear asking you to confirm that you wish to delete the transaction.
Click the 'Delete' button and this will remove the payment from the expense. This will take you back to the face of the expense claim, so click the Update Expense option and this will change the expense back to outstanding.